Simplify the following expression: $t = \dfrac{y^2 - 8y - 20}{y + 2} $
First factor the polynomial in the numerator. $ y^2 - 8y - 20 = (y + 2)(y - 10) $ So we can rewrite the expression as: $t = \dfrac{(y + 2)(y - 10)}{y + 2} $ We can divide the numerator and denominator by $(y + 2)$ on condition that $y \neq -2$ Therefore $t = y - 10; y \neq -2$